Fishermen and rescue workers hauled dozens of people out of the sea after a ferry sank in the central Philippines on Friday, but at least two passengers drowned, authorities said.
In the latest disaster to hit the nation's notoriously dangerous sea transport industry, the ferry mysteriously sank in calm weather before dawn about two kilometres (1.2 miles) from Burias island.
Fishermen on small outrigger motorboats were among the first to arrive on the scene and saved many lives, said local coastguard deputy chief Bayani Belisario.
"They (the passengers) were floating in their life jackets and the rescuers picked them out of the water," Belisario told AFP.
He said several people from the sunken ship were also able to make the long swim to the shores of Burias on their own.
A navy plane and a coastguard ship, diverted from taking part in maritime exercises in Indonesia, joined the search and 55 people were rescued throughout the morning, according to the authorities.
But Belisario said the bodies of two women were recovered from the water.
Coast guard volunteer Amadeo Tan told ABS-CBN television that his wife, who was on the ship, called him by her mobile phone to say the boat had sank.
"She was already floating in the water. I did not think twice and we rushed to the site," said Tan, a resident of Masbate island, the ferry's destination.
Tan said his group rescued dozens including his wife, who was unhurt but left traumatised by the incident.
The ferry's manifest listed 35 passengers and 22 crew aboard but local civil defence chief Raffy Alejandro said there could be as many as seven people still missing.
Seven drivers and assistants who brought two buses and a truck aboard the roll-on, roll-off ferry may not have been listed because they travelled for free, Alejandro told AFP.
He said the cause of the sinking was not yet known but the ship's captain, who was among those rescued, reported the vessel may have been unbalanced by the buses and large truck.
"He said it happened so quickly. It just went down in the darkness," Alejandro said, adding the waters and weather were calm.
The type of roll-on, roll-off ferry that sank is commonly used in the Philippines to transport people, vehicles and cargo throughout the archipelago of more than 7,100 islands.
Alejandro said the ferry, the MV Lady of Mount Carmel, was not believed to have been overloaded as it sought to make its regular journey of about four hours between the two major provinces of Albay and Masbate, more than 300 kilometres southeast of Manila.
Sea accidents are common in the Philippines due to poor safety standards and overloading.
The world's deadliest peacetime maritime disaster occurred near Manila in 1987 when a ferry laden with Christmas holidaymakers collided with a small oil tanker, killing more than 4,300 people.
In 2008, a huge ferry capsized during a typhoon off the central island of Sibuyan, leaving almost 800 dead.
Graphic map showing the island of Burias in central Philippines where a ferry carryring 57 people on board sank on Friday.
Philippine Coast Guard (PCG) spokesperson Arman Balilo points to a map where the ferry 'MV Lady of Mount Carmel' capsized about two kilometres (1.2 miles) from Burias island, on June 14, 2013.
This file photo shows coastguard rescue team searching for survivors after an accident off southern island of Mindanao, on August 26, 2008. Fishermen and rescue workers hauled dozens of people out of the ocean after a ferry sank in the central Philippines on Friday, but at least two passengers drowned and 13 others were missing, authorities said.